About 8 months ago my ML out of nowhere started slipping at highway speeds randomly for about a day, and then the following day it began hard shifting and slipping until it would not move at all. I parked the truck and haven't touched it until yesterday. I replaced the 13-pin connector which was completely covered in transmission fluid. The truck will drive for about 5 minutes then will just slip and make a whining noise. The truck will move until i put it in reverse or try shifting gears then it appears to be in neutral? I have never had an issue with slipping or hard shifting before. I am pulling a code P0715 which could be caused by a number of things. What should be my first approach? Should i clean the conductor board? or just replace it? Thanks!